Battle of the Operating Systems

Bytelines

Sol Libes Byte Magazine

March 1982

When IBM announced that Digital Research's CP/M-86 disk operating system (DOS) would be supported by the IBM Personal Computer, visions of plentiful software danced in the heads of many potential purchasers, who were thinking of the legion of programs that are available for use under CP/M-80, the operating system that has become the de facto standard for users of 8-bit 8080-, 8085-, and Z80- based computers.

But the visions may soon be dancing to a different tune. Despite the similarity of the two DOSes, an operating system does not change the character of the hardware it runs on, and the hard fact remains that software written and compiled for the Z80 microprocessors cannot be immediately and easily run on the 8088 16-bit microprocessor. Programs must be converted and/or rewritten to be compatible, taking time and effort.

Meanwhile, confidence is increasing in IBM's Personal Computer DOS, which was written for IBM by Microsoft Inc., of Bellevue, Washington. As of this writing, all of the application software announced by IBM runs under this DOS, and many program authors report that converting CP/M-80 programs to run under the Microsoft system is easier than converting them to run under CP/M-86.

Microsoft will be releasing the operating system, which it will call "MS-DOS," to be run on 16-bit computer systems from other manufacturers. And Lifeboat Associates of New York City, the world's largest distributor of 8-bit CP/M software, has committed itself to support Microsoft's MS-DOS, under the name "SB-86," for the 16-bit world. Lifeboat plans to make SB-86 available for a wide variety of machines in the same way that it made CP/M-80 available off the shelf for close to 40 different 8-bit computers. Lifeboat says it will convert all of its current software packages to run under SB-86.

There is no doubt that CP/M-80 will continue to dominate the 8-bit DOS market. But the 16-bit race for dominance is still on, and CP/M-86 is in the pack along with MS-DOS and the multiuser operating systems: Digital Research's own MP/M-86, Oasis-86 from Phase One Systems, Multi-OS from Infosoft Systems, and Microsoft's Unix-like Xenix operating system.